[OSM-dev] proposal to kill areas

[Andy Robinson]

Etienne [mailto:80n80n at gmail.com] wrote:
>Sent: 22 July 2006 22:40
>To: Andy Robinson
>Cc: SteveC; dev at openstreetmap.org
>Subject: Re: [OSM-dev] proposal to kill areas
>
>Andy
>Interesting point.  What I think you are saying is that an area could/can
>be defined as the boundary of a set of nodes that share a common attribute.
>
>This would work quite nicely for many situations.  All the phoneboxes/post
>boxes/buildings with an NW1 postcode could be used to define the NW1 postal
>area.  Nobody actually goes out and traces the boundary (probably, nobody
>actually knows the real physical boundary), but each phonebox that is
>tagged with an NW1 code helps to define the area.
>
>Similarly there have been discussions in the past about the difficulty of
>walking administrative boundaries.  If enough nodes within the
>administrative unit are tagged as such then the actual line of the boundary
>is moot.
>
>There is probably room for a physical boundary based definition as well as
>a collection of nodes based definition.  But, the physical boundary based
>definition is actually just a set of nodes that have a common attribute;
>they all belong to the same way element.
>
>Very interesting idea...
>
>Etienne
>

Thanks for summing it up better than I could have ;-)

The physical boundary that we can physically map is less of a problem. I
already had a "boundary" key in Map Features for that very purpose so it
really doesn't need to be more complicated than a way. 
The container of nodes would work exactly as you surmise. I just haven't
done it yet although I can see that a trial run with post_boxes is a good
idea for me too. I've just realised that I have been tagging ways with
postal_code data but it would have been better to code the nodes as well. Oh
well, more editing. Thank goodness for JOSM :-)

Cheers

Andy


>
>On 7/22/06, Andy Robinson <Andy_J_Robinson at blueyonder.co.uk > wrote:
>
>	I've been really rather taken aback by the variety of argument on
>this
>	matter yet nobody has really come back with a straight forward
>response to a
>	valid question.
>
>	For me the feature that I think of as an area I also think of as
>volume, in
>	other words a container. The container has sides (edges in 2D) and
is
>the
>	receptacle into which I pour all the information both related to the
>	container and information residing within in. I think of this like a
>	library. The library itself is a structure which has information
>about
>	itself (what time it opens etc). Within it there are shelves
>containing
>	books. While the books themselves may not be properly described by
>the
>	library (I can read them independently outside the library doors)
the
>	library does know that a particular book exists on its shelves.
>
>	A map is no different in this respect. It contains location
>information
>	within fixed or loose boundaries (areas).
>
>	So my belief is that OSM only needs to find a simple way of defining
>the
>	container, and this might be done by tagging the items belonging to
>it
>	rather than defining a fixed boundary and then all the data being
>either in
>	or out (ie no flexibility). A good mapping example is when a new
>housing
>	estate goes up on Greenfield, it's a lot easier to redefine the
>limits of
>	the urban conurbation by its elements than to have to redefine the
>limits of
>	the boundary as a separate entity.
>
>	Being able to group and container data should open up a lot more
>	possibilities for information stored and used from OSM. It includes
>time
>	dependent data as well. Its one of the aspects of OSM that got me
>interested
>	in the start. The ability to tag any bit of map data with much more
>than you
>	can on a traditional map.
>
>	So to answer Steve's question, I personally don't think we need
><areas>. And
>	since we can effectively create containers with the tagging of data
>	(although that may not necessarily be the most efficient way to do
it
>in a
>	db sense) then we probably don't need anything in its place either.
>
>	Cheers
>
>	Andy
>
>	Andy Robinson
>	Andy_J_Robinson at blueyonder.co.uk
>
>	>-----Original Message-----
>	>From: dev-bounces at openstreetmap.org [mailto:dev-
>bounces at openstreetmap.org]
>	>On Behalf Of SteveC
>	>Sent: 20 July 2006 15:20
>	>To: dev at openstreetmap.org
>	>Subject: [OSM-dev] proposal to kill areas
>	>
>	>There are only 4 areas in OSM and osmarender treats certain tagged
>ways
>	>as an area. I figure it'd make the server simpler and make client
>area
>	>support simpler if 'area=true' on a way made it in to an area.
>	>
>	>Functionally, if they were working, an area is identical to a way
>	>already.
>	>
>	>Thoughts?
>	>
>	>have fun,
>	>
>	>SteveC steve at asklater.com http://www.asklater.com/steve/
>	>
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